Polymer/layered silicate nanocomposites are a new class of materials, obtained by the dispersion of the very high-aspect-ratio clay particles into a polymer matrix [1]. These materials have distinct advantages over their macro- and micro-composite counterparts including higher modulus, outstanding diffusion barrier properties and flame retardancy. Recently, significant attention has been given to biocompatible and/or biodegradable polymers, both from biomedical and ecological perspectives. In case these polymers come from renewable sources, they are even more exciting. If they are mixed with the silicate particles via a solvent-free technique, they can offer an integrative route for producing such advanced hybrid materials in accordance with the principles of green materials design and production.

In the present study, the results from an initiative undertaken to produce such environmentally-benign nanocomposites with potential applications in the field of biomedical products (high-added value products) and in packaging (low-added value products) are presented. More specifically, nanocomposites made of three different polymers, namely poly(ε-caprolactone) (PCL), poly(3-hydroxybutyrate) (PHB) and high-amylose starch, with various amounts of organically modified montmorillonite were produced in a ThermoHaake MiniLab micro-exruder/-compounder. The morphology of the prepared hybrids was investigated by X-ray diffraction, while their thermal characteristics were studied by differential scanning calorimetry. Thermal degradation studies by thermogravimetric analysis revealed that the nanocomposites display increased thermal stability, while their mechanical testing showed improved properties over the virgin polymers.

Acknowledgements

This work was supported by the Region of Western Macedonia (Greece) through the PEP grant with MIS 105545 to I. Z.

References

1. Marras, S.I., Zuburtikudis, I., Panayiotou, C., Eur. Polym. J., 43 (2007) 2191.

2. Ray, S.S. and Bousmina, M. Prog. Polym. Sci., 50 (2005) 962.